Glaciers Flashcards
1
Q
what holds the most water in the hydrosphere
A
Oceans - about 97%
2
Q
what are the two largest non-ocean component of water distributed in hydrosphere
A
largest is glaciers (2.15%)
groundwater - 0.62%
3
Q
what is a glacier
A
a large accumulation of LAND ice affected by present of past flowage
4
Q
how do glaciers behave
A
behave plastically (ie they flow as one large mass of ice without breakage)
5
Q
what does it mean that glaciers are plastic
A
that they move as a flow, one large mass of ice moving without breaking
6
Q
are glaciers accumulation of sea ice
A
NO - land ice
7
Q
what latitudes have glaciers shaped landforms
A
middle and high latitudes
8
Q
what is an example of a country largely impacted by glaciers
A
Canada
9
Q
why are large bodies of ice plastic
A
because the pressure on the bottom of the mound of ice compresses it
10
Q
can ice slide down a slope
A
YES with aid of gravity
11
Q
how do glacial ice sheets affect global warming
A
- they reflect sunlight = high albedo = cooling effect
- affects global heat transfer = blocks the movement of heat through the landscape = cooling effect
- volume of ice affects sea levels = the buildup of water ON LAND lowers the sea level
12
Q
what are 6 types of glaciers
A
- valley/alpine
- ice sheet
- ice cap
- outlet glaciers and ice streams
- piedmont glaciers
- tidewater glaciers
13
Q
what are alpine/valley glaciers
A
long, narrow mountain glacier occupying the FLOOR of a trough-like valley
14
Q
what is the driving force of alpine/valley glaciers
A
gravity
15
Q
what are two ways alpine/valley glaciers move
A
basal sliding
plastic flow
16
Q
describe basal sliding
A
when the temperature at the base of the glacier is above melting temp and so melting can occur.
Melting facilitates glacier movement as friction is reduced and so the ice can slide over the valley floor.
17
Q
describe plastic flow
A
the internal flowage of the ice based on the weight on top of the bottom layer of glacier
18
Q
what does the rigid zone mean for alpine/valley glaciers
A
the top of the glacier where ice behaves brittlely (not plastic like at bottom)
19
Q
what forms in the rigid zone of alpine/valley glaciers
A
crevasses
20
Q
describe the upper and lower part of alpine/valley glaciers
A
upper - glacier is brittle
lower - glacier is plastic
21
Q
contrast zone of accumulation vs zone of ablation for glaciers
A
accumulation
- glacier is growing (based on gaining more snow than melting)
ablation
- glacier is evaporating/melting (receding)
22
Q
how can alpine glaciers slide downhill
A
on mud and meltwater
23
Q
what is the rate of movement for alpine glaciers
A
about a few centimeters/day to several meters/day
24
Q
is the movement of alpine glaciers always slow
A
NO
25
what is a surge in terms of alpine glaciers
rapid movement of alpine glaciers (up to 60 m/day) for several months
26
what type of glacier is this
alpine/valley glacier
27
what are ice sheets
large thick plate of glacial ice moving outwards in all directions
28
how do ice sheets affect global climate
- reflect sunlight = cooling effect
- affects the entire global heat transport NOT just local ones because of sheer volume
- lowers sea levels
29
how do ice sheets move
they start from a central high location and move downward/outward in all directions
30
what are two ice sheets on Earth
- Greenland ice sheet
- Antarctic Ice Sheet
31
what type of glacier is this
ice sheets
32
what is an ice cap
a glacier that flows on top of topography
33
how does an ice cap glacier grow
starts at top of topography and flows in all directions
34
how is an ice cap similar yet different to ice sheet
both start at topographical highs and flow in all directions but ICE CAPS ARE SMALLER
35
what type of glacier is this
ice cap
36
what type of glacier is this
Piedmont glacier
37
what are outlet glaciers and ice streams
valley glacier or stream of ice that grows out of an ice cap or ice sheet
38
what do outlet glaciers form
fjords
39
what large body of ice does a outlet glacier flow from
ice cap OR ice sheet
40
what type of glacier is this
outlet glacier/ice stream
41
what are piedmont glaciers
an outlet glacier that forms an ALLUIAL FAN SHAPE
42
where do piedmont glaciers form
where there is a transition from steep topography to gentle sloping topography
43
how do tidewater glaciers form
when a valley glacier or outlet glacier starts to grow out onto the sea
44
what two types of glaciers can form a tidewater glacier
valley glacier or outlet glacier
45
what type of glacier is this
tidewater glacier
46
what are the steps for building a glacier
1. glacier ice builds up when snowfall in winter EXCEEDS the snow melt in summer
2. each annual layer of snow, melt and refreeze cycle hardens the remaining snow
3. over time the accumulation of hardened ice compresses the lower layers into hard crystalline ice
4. once ice is thick enough the lower layers have enough compression from upper layers that the mass flows plastically
47
what temperatures are best for glacier formation
temps are low and snowfall is high
48
what are the steps for glacier formation in a nutshell
snow ---> firn (compressed snow) ----> glacier ice
49
what are some methods of glacier wastage (how glacier lose ice)
1. melting
2. evaporation
3. calving into icebergs
50
what does calving mean
when tidewater glaciers break off from main outlet glacier or valley glacier into the ocean
51
what are negative and positive glacier budgets
negative
- receding glacier
- loss of ice is more than ice accumulation
positive
- advancing glacier
- more ice accumulating than is lost
52
what glacier budget is this
advancing glacier
positive budget
53
what glacier budget is this
receding glacier
negative budget
54
what divides the zones of accumulation and wastage
snow line
55
what is zone of accumulation
part of a glacier's surface, usually at higher elevations, where there is net accumulation of snow
56
what zone of a glacier is associated with the production of firn
zone of accumulation
57
zone of wastage
The lower portion of the glacier where the ice is lost
58
what is the terminus
the end of the glacier movement associated with the budget
59
what kind of terminus is associated with positive budget
end of glacier moving downward (advancing the glacier)
60
what kind of terminus is associated with negative budgetS
end of glacier moving upwards (receding glacier)
61
what zone of formation is 1
zone of accumulation
62
what zone of formation is 2
snow line
63
what zone of formation is 3
zone of wastage
64
what are some under glacier methods of erosion
1. abrasion
2. plucking
3. polishing and rounding
4. rock flour
5. striation
65
describe the 5 under glacier methods of erosion
1. abrasion
- the glacial ice holds material frozen in the ice that rub against the ground
2. plucking
- ice picks up loose bedrock from the environment and carries it along and running it across the surface
3. polishing and rounding
- the abrasion of the rock by the glacier renders the rock so smooth it reflects light
4. rock flour
- the component of glacier sediment that is much finer than sand produced by the constant grinding at the base of the ice.
5. striation
- a series of long, straight, parallel lines or grooves scratched onto a bedrock surface by rock fragments lodged in the base of a moving glacier
66
what type of under glacial erosion shows the direction it is moving
the polishing and striation of bedrock
67
what are above glacier erosion methods
- frost wedging
- erosion to steepen the slope
68
what type of under erosion is this
glacial striation
69
what types of glacial erosion is this
plucking leading to abrasion
70
what are the erosional landscapes associated with alpine glaciers
1. U - shaped valley
2. hanging valley
3. glacial troughs
4. fjords
5. rounded knobs (roche mountonnees)
6. crag and tail
7. rock steps
71
what are some erosional features associated with alpine glaciation
1. cirque
2. tarns
3. col
4. horn
5. arete
6. truncated spurs
7. triangular facets
72
what are U shaped valleys
a valley that has been carved out by a glacier where the profile of the valley is altered by erosional forces of the glacier (turning the original V shaped valley to U shaped)
73
what erosion landscape is this
u shaped valley
74
what is a glacial hanging valley
found higher than the floor of the main valley, up on the sides of larger U-shaped valley and form from tributary valleys (smaller glaciers)
75
what erosion landscape is this
hanging valley
76
is there a height difference between a hanging valley and a U shaped valley
YES - hanging valley is further up than the floor of main valley
77
what are glacial troughs
deep, steep sided rock trench formed by alpine glacier erosion
78
what are fjords
forms when a U-shaped valley extends to the ocean and once the glacier recedes the sea level floods the old glacier valley
79
what erosion landscape is this
Fjord
80
what are rounded knobs or roche moutonnees
asymmetric bedrock bumps or hills
81
describe the two sides of a roche moutonnees
Stoss
- gently sloping side where the glacier climbs up and over the rock
Lee
- face that is usually blunter where the glacier drops off the rock face (rock face ends)
82
what erosion landscape is this
Roche Moutonnees
83
what are craig and tails
a large mass of resistant rock and a gentle sloping tail of less resistant rock caused by passage of glacier over an area of hard rock
84
what is an example of craig and tail
Edinburgh Castle
85
how do craig and tail features DIFFER from roche moutonnee
1. the craig and tail is LARGER
2. the craig and tail is the opposite to the roche moutonnee and has DOWNSLOPE in the direction of ice flow
86
describe the type of rock that forms the tail and craig of the erosion feature
tail = softer rock = more erosion
craig = resistant rock = less erosion
87
how are rock steps formed
when there are rocks of varying resistances covered by a glacier where lower resistant rocks will leave a hollow in the landscape and harder rocks are more resistant to erosion and will sit higher up
88
what erosion landscape is this
craig and tail
89
what erosion landscape is this
rock steps
90
what are cirques
bowl-shaped like depression carved into mountains and valley sidewalls at HIGHER elevations by glacier
91
what erosion landscape is this
cirque
92
what erosion landscape is this
tarn
93
what are tarns
small mountain lake occupying cirques formed as a glacier melts (NO streams filling it)
94
what holds the tarn within the cirque
moraine
95
col
the lowest area (mountain pass) between two cirques across an arete
96
what erosion landscape is this
Col
97
where is the easiest area to cross between glaciers
across a col
98
horn
pointed peaks bounded on at least three sides by aretes with flat faces
99
what erosion landscape is this
horn
100
arete
thin, jagged crest that separates two adjacent glaciers
101
describe the appearance of aretes
rugged ridgelines that look like serrated knifes or saw blades
102
low pass points on the serrated surface of aretes
cols
103
what erosion landscape is this
aretes
104
truncated spurs
found between hanging valleys and are created when a former tributary valley has been sliced off by larger LOWER glacier
105
how are triangular facets formed
by glacial truncation of a spur
106
where are triangular facets found
above the main glacier valley between hanging valleys
107
what erosion landscape is this
truncated spur
108
what are the depositional landscapes for continental glaciers (7)
1. moraines
(lateral, terminal, recessional, end, medial, ground)
2. drumlin
3. esker
4. kames and kettle
5. hummocky terrain
6. outwash plain
7. glacial erratic
109
what is the method of forming all glacial deposition landscapes
glacial drift
110
what is glacial drift
general term for all varieties and forms of rock debris deposited by ice sheets
111
what are two kinds of glacial drift
stratified drift and till
112
stratified drift VS till
stratified drift
- layers of SORTED clays, silts, sand or gravel deposited by MELTWATER STREAMS OR LAKES
Till
- UNSTRATIFIED mixture of rock fragments of all sizes, deposited by ICE
113
does Till require water to deposit
NO - uses the ice itself
114
stratified drift OR till
TILl
115
stratified drift OR till
stratified drift
116
moraines
depositional feature based on the accumulation of rock debris carried by a glacier before being deposited
117
how are moraines deposited
based on glacial drift and the deposition of ice (so its till)
117
where do moraines form
in and around glacier ice
118
what are the different types of moraines
lateral
terminal
recessional
end
medial
ground
119
lateral moraines
form at the SIDE of the glacier
120
terminal moraines
FARTHEST END MORAINE showing the GREATEST advance of the glacier
121
recessional moraines
forms at the current terminal of the glacier (closest to the mass of ice)
122
end moraines
any moraine deposited at the terminal/foot of the glacier
123
medial moraines
forms BETWEEN two glaciers (where they meet)
124
ground moraines
forms under the glacier ice ON THE GROUND
125
1
lateral moraine
126
2
medial moraine
127
3
end moraine
128
4
recessional moraine
129
5
ground moraine
129
6
terminal moraine
130
drumlin
depositional feature looking like smoothly rounded, oval hills of glacial TILL formed by moving ice over bedrock
131
what other depositional feature are drumlins found with
with esters
132
describe the sides of a drumlin
steep side = where the glacier is coming from and where it started to climb over the bedrock
gentle side = where the glacier is going after climbing over the bedrock
133
what depositional feature is this
drumlin
134
1
esker
135
4
kettle lakes
135
3
end moraine
136
2
drumlin fields
137
what is an esker
a narrow often sinuous looking embarkment of coarse gravel and boulders
138
how are eskers deposited
by a meltwater stream (stratified drift)
139
what depositional feature is this
esker
140
describe kames
irregularly shaped hill or mound composed of STRATIFIED sand, gravel or till
141
what other depositional features are kames often associated with
1. kettle holes
2. end moraines
142
what type of terrain are kettles and kames apart of
hummocky terrain
143
how are kames deposited
glacier melt (stratified drift)
144
how do kettles form
due to melting of large ice blocks which push down the topography below them with their weight
144
kettles
depressions in the OUTWASH plains
145
hummocky terrain
uneven or undulating surface texture with roughness varying between smooth and rough textures
146
what type of depositional feature is this
kettle
147
what type of depositional feature is this
hummocky terrain
148
outwash plain
occurs at the front of a melting glacier and is a generally flat area dominated by braided rivers
149
what depositional feature is this
outwash plain
150
glacial erratic
piece of rock that differs from the size and type of rock native to that area where it was found
151
how to glacial erratics end up where they do
based on being carried by glacial ice over long distances
152
what is Big Rock in Okotoks an example of
depositional feature of erratic
153
what depositional feature is this
glacial erratic
